Fourteen Israeli and three foreign hostages were released Sunday, the IDF said.
Thousands of people have died and thousands more have been injured since the militant group Hamas launched an unprecedented surprise attack on Israel on Oct. 7 and Israel retaliated with a bombing campaign and total siege of the neighboring Gaza Strip, leaving the region on the verge of all-out war.
Click here for updates from previous days.
The latest outbreak of war between Israel and Hamas, the Palestinian militant group that governs the Gaza Strip, has passed the four-month mark.
In the Gaza Strip, at least 30,228 people have been killed and 71,377 others have been wounded by Israeli forces since Oct. 7, according to Gaza's Hamas-controlled Ministry of Health.
In Israel, at least 1,200 people have been killed and 6,900 others have been injured by Hamas and other Palestinian militants since Oct. 7, according to the Israel Defense Forces.
There has also been a surge in violence in the Israeli-occupied West Bank. Israeli forces have killed at least 395 people in the territory since Oct. 7, according to the Palestinian Ministry of Health.
The ongoing war began after Hamas-led militants launched an unprecedented incursion into southern Israel from neighboring Gaza via land, sea and air. Scores of people were killed while more than 200 others were taken hostage, according to Israeli authorities. The Israeli military subsequently launched retaliatory airstrikes followed by a ground invasion of Gaza, a 140-square-mile territory where more than 2 million Palestinians have lived under a blockade imposed by Israel and supported by Egypt since Hamas came to power in 2007. Gaza, unlike Israel, has no air raid sirens or bomb shelters.
The IDF and General Security Service killed five senior Hamas officials in Gaza, IDF spokesman Daniel Hagari said Sunday, adding they were "key figures and key partners" in the Oct. 7 attack.
Hagari also said the war will not end until all the hostages are returned.
"This is the ethical and moral duty of every IDF soldier and the bodies of the defense establishment," he said.
Israeli Prime Minister Benjamin Netanyahu toured the Gaza Strip on Sunday and vowed the return of all of the hostages taken by the Hamas terror group, according to the prime minister's office.
Netanyahu spent time with Israeli commanders and fighters and visited one of the Hamas tunnels uncovered by Israeli forces, the prime minister's office said in a statement.
"We are here in Gaza with our heroic fighters," Netanyahu said in a video released by his office showing him wearing a helmet and flak jacket, and surrounded by Israeli soldiers. "We make every effort to return our abductees, and eventually we will return them all. We have three goals for this war: eliminate Hamas, return all our abductees, and ensure that Gaza does not become a threat to the State of Israel again."
Netanyahu added, "We continue until the end -- until victory. Nothing will stop us, and we are convinced that we have the power, the strength, the will and the determination to achieve all the war's goals, and we will."
-ABC News' Bruno Nota and Jordana Miller
President Joe Biden praised the release of hostages Sunday from the Gaza Strip and said he hopes the four-day cease-fire will be extended.
"Look, you know the deal calls for every 10 hostages released, we extend another day. So, I'm hopeful this is not the end, it's going to continue. But we don't know. But I get a sense that all the players in the region, even the neighbors who haven't been directly involved [up] to now, are looking for a way to end this so the hostages are all released and Hamas is completely, how can I say it, no longer in control of any portion of Gaza," Biden said at a press conference.
"I'd like to see the pause go on as long as prisoners keep coming out," he added.
Biden said there are probably other militant groups that have hostages in the Gaza Strip, and that the condition of the other Americans being held in Gaza is unclear.
The president's remarks come as 4-year-old Abigail Idan was among the hostages released Sunday.
Idan's parents were killed in front of her during the October attack in southern Israel, U.S. officials have said.
"She's been through a terrible trauma," Biden said. "What she endured is unthinkable."
Israel and Hamas are currently on the third day of a four-day pause in fighting during which Israel plans to release 150 Palestinians and Hamas will release 50 of the over 200 people it is thought to have taken hostage on Oct. 7.
Abigail Idan, a 4-year-old Israeli American, was among the 17 hostages released to the Red Cross on Sunday, according to the Israeli prime minister's office.
Abigail, who turned 4 on Friday, was taken hostage on Oct. 7 after her parents were killed by Hamas terrorists, according to Israeli officials.
Another Israeli American, Aviva Adrian Siegel, 62, was also freed on Sunday, the Israeli prime minister's office said.
"We were overjoyed. Couldn't believe it," Siegel's brother-in-law, David Siegel told ABC News, adding that the family had been doubtful she would be released.
The Israel Defense Forces said 13 hostages were returned to Israel accompanied by IDF forces and are now in Israeli territory, with 12 being escorted to the Hatzerim base and another having gone to a hospital. Four more hostages are on their way to the Rafah crossing, the IDF said.
Other Israeli hostages released on Sunday were identified by the Israeli prime minister's office as:
